Remifentanil is a synthetic opioid, first introduced into clinical practice in 1996. Its unique pharmacokinetic profile has resulted in a gradual increase in its popularity in paediatric anaesthesia. It is an opioid of high potency and rapid clearance, consequently lacking problems of accumulation. These characteristics give it a high degree of predictability and it has become an attractive choice for a wide variety of anaesthetic challenges, from premature neonates to the elderly. Neonates and infants have a higher clearance than older children and, as a result, remifentanil has additional benefits in this group. Remifentanil can be described as the only consistently predictable opioid in paediatric practice.